Chemical compounds beta-(meta-hydroxyphenol)-isopropylamines



Patented Mar. 14, 1944 CHEMICAL COIVIPOUNDS fl-(META-HY- DROXYPHENOL) *ISOPROPYLAMINES Gustav Hildebrandt, Mannheim, Germany, assignor to E. Bilhuber Inc., Jersey City, N. J.

No Drawing. Application December 27, 1937, Serial No. 181,988. In Germany January 2, 1937 3 Claims.

This invention relates to new and valuable chemical compounds comprising p-(meta-hydroxyphenyl) -isopropylamines of the general type formula in which R designates hydrogen, an alkyl radical, for example methyl, ethyl, propyl, isopropyl, butyl, isobutyl, isoamyl, etc. or a cycloalkyl radical, for example cyclohexyl, ortho-, metaor paramethylcyclohexyl, tetrahydronaphthyl, decahydronaphthyl etc.

It has already been proposed to prepare 13- (para-methoxyphenyl) -iscpropylmethylamine by condensing ,B- (para-methoxyphenyl) -isopropylamine with benzaldehyde to form the corresponding Schiffs base, treating the Schifis base with methyl iodide or a similar compound and hydrolysin the resulting addition product with aqueous acid.

According to another proposal fi-(para-methoxyphenyl) -isopropylmethylamine is prepared by treating para-methoxy-benzylmethylketone with reagents which yield formic acid and methylamine. The formyl compound of p-(para-methoxyphenyl) -isopropylmethylamine is obtained thereby and is saponified with dilute mineral acid. The fl-(para-hydroxyphenyl)-isopropylmethylamine may be obtained from the B-(para-methoxyphenyl)-isopropylmethylamine obtained by either of the preceding processes, by eliminating the methoxy group with strong acid. According to known data this compound is physiologically active and is saidto exert efiects similar to those of ephedrine.

According to this invention it has been found that favourable therapeutic properties are possessed not only by the aforesaid derivative of B-(hydroxyphenyl) -isopropylamine, in which the hydroxy group is in the para-position, but that fl-(meta-hydroxyphenyl) -isopropylamines in general possess similar favourable therapeutic properties.

The new compounds of this invention are prepared by treating B-(meta-methoxyphenyl) -isopropylamines, which correspond to the general type formula (Cl. 260570.8) E

in which R designates hydrogen, an alkyl radical, for example methyl, ethyl, propyl, isopropyl, butyl, isobutyl, isoamyl etc. or a cycloalkyl radical, for example cyclohexyl, ortho-, meta-. or paramethyl-cyclohexyl, tetra-hydronaphthyl, decahydronaphthyl etc., with strong acids whereby the methoxy group is eliminated.

For eliminating the methoxy group use is preferably made of strong mineral acids, particularly hydrohalogenic acids, for example hydrobromic acid. The treatment is efiected with concentrated acids, for example with 48% hydrobromic acids The treatment may be promoted by heating. The methoxy compound is preferably boiled with concentrated acid.

The ,B-(meta-hydroxyphenyl) -isopropylamines used as starting materials for the preparation of the ,8 (meta-hydroxyphenyl)-isopropylamines may be prepared in any desired manner. They are however most suitably prepared by condensing' meta methoxybenzyl methylketone with amines, corresponding to the general formula RNHz, wherein R designates hydrogen, an alkyl radical or a cycloalkyl radical and simultaneously or subsequently reducing the condensation product.

Example 50 gms. of meta-methoxybenzylmethylketone, 30 gms. of activated aluminium turnings, 1000 cos. of absolute ether and cos. of 40% aqueous methylamine solution are boiled under reflux for 6 hours on a water bath. After separating the undissolved constituents the solution is evaporated down and thereafter taken up in dilute acid. Non-basic constituents are removed from the solution by extraction with ether. The resulting fi- (meta-methoxyphenyl) isopropylmethylamine is precipitated by adding alkali. (Boiling polntm, 130 to 135 C.) Yield: -90%.

By boiling the base with the five-fold quantity of 48% hydrobromic acid for one hour under reflux the methoxy group is eliminated. (meta-hydroxyphenyl)-isopropylmethylamine is recovered therefrom in known manner. The hydrochloride of the base forms beautiful crystals which sinter at 128 to 130 C. and melt at 182 C. The yield amounts to about What I claim is:

1. The chemical compounds p-(meta-hydroxyphenyl) -isopropylamines of the formula HOCsH|-CH:-CH-CH| v HN.R wherein R is a lower alkyl radical.

' 2. A metamethoxybenzylmethyl-carbinmethyl- 3. A metahsdroxybenzylmethyl-carblnmethylamine base having the formula amine base having the lormula.

cm-ca-cm I mien. Nacm 0cm on GUSTAV HIIDEBRANUI. 

